(function (f) {

    'use strict';

    /* istanbul ignore else */
    if (typeof exports === 'object' && exports != null &&
        typeof exports.nodeType !== 'number') {
        module.exports = f();
    } else if (typeof define === 'function' && define.amd != null) {
        define([], f);
    } else {
        var base64 = f();
        var global = typeof self !== 'undefined' ? self : $.global;
        if (typeof global.btoa !== 'function') global.btoa = base64.btoa;
        if (typeof global.atob !== 'function') global.atob = base64.atob;
    }

}(function () {

    'use strict';

    var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

    function InvalidCharacterError(message) {
        this.message = message;
    }

    InvalidCharacterError.prototype = new Error();
    InvalidCharacterError.prototype.name = 'InvalidCharacterError';

    // encoder
    // [https://gist.github.com/999166] by [https://github.com/nignag]
    function btoa(input) {
        var str = String(input);
        for (
            // initialize result and counter
            var block, charCode, idx = 0, map = chars, output = '';
            // if the next str index does not exist:
            //   change the mapping table to "="
            //   check if d has no fractional digits
            str.charAt(idx | 0) || (map = '=', idx % 1);
            // "8 - idx % 1 * 8" generates the sequence 2, 4, 6, 8
            output += map.charAt(63 & block >> 8 - idx % 1 * 8)
        ) {
            charCode = str.charCodeAt(idx += 3 / 4);
            if (charCode > 0xFF) {
                throw new InvalidCharacterError("'btoa' failed: The string to be encoded contains characters outside of the Latin1 range.");
            }
            block = block << 8 | charCode;
        }
        return output;
    }

    // decoder
    // [https://gist.github.com/1020396] by [https://github.com/atk]
    function atob(input) {
        var str = (String(input)).replace(/[=]+$/, ''); // #31: ExtendScript bad parse of /=
        if (str.length % 4 === 1) {
            throw new InvalidCharacterError("'atob' failed: The string to be decoded is not correctly encoded.");
        }
        for (
            // initialize result and counters
            var bc = 0, bs, buffer, idx = 0, output = '';
            // get next character
            buffer = str.charAt(idx++); // eslint-disable-line no-cond-assign
            // character found in table? initialize bit storage and add its ascii value;
            ~buffer && (bs = bc % 4 ? bs * 64 + buffer : buffer,
                // and if not first of each 4 characters,
                // convert the first 8 bits to one ascii character
            bc++ % 4) ? output += String.fromCharCode(255 & bs >> (-2 * bc & 6)) : 0
        ) {
            // try to find character in table (0-63, not found => -1)
            buffer = chars.indexOf(buffer);
        }
        return output;
    }

    return {btoa: btoa, atob: atob};

}));